A variety of slender connecting members have been developed to transmit tensile and/or compressive loads between structures. These members may comprise an elongate body having a fixed or adjustable fitting on each end thereof forming the points where the member may be attached to structures. For example, in the aircraft industry, tie rods may be used for mounting and supporting overhead storage bins, lavatories, galleys, ceilings, equipment racks, etc. Typical tie rods used in aircraft may comprise a hollow cylinder formed of metal such as aluminum, or a composite material such as carbon fiber epoxy. The cylinder includes tapered ends provided with attachment fittings formed of metal or composite material, depending upon the application.
The tie rods described above used in aircraft applications are effective, durable and relatively lightweight. However, since several hundred tie rods may be used in a typical commercial or military aircraft, any reduction in tie rod weight may represent a significant overall weight reduction in the aircraft.
Composite members used to transmit tensile or compressive loads are known in which an open lattice structural shell is formed by interlacing longitudinal and helical filaments that form a truss-like grid. The longitudinal filaments primarily carry axial and bending loads, while the helical filaments both stabilize the longitudinal filaments and carry both torsion and transverse shear forces. Bundles of the filaments are held in a resin matrix, which after curing, form strong, lightweight, stiff structural members.
A problem exists in utilizing the lightweight open lattice composite body described above for tie rod and/or strut applications because of the difficulty of attaching the ends of the tie rod/strut to the individual filaments at the end of the body, either before or after curing.
Accordingly, there is a need for a composite tie rod having a lightweight, open lattice body that includes fittings allowing either conventional or unique tie rod ends to be connected to the body. There is also a need for a method of producing these tie rods and the related fittings.